OBJECTIVE Most older people have suboptimal levels of habitual physical activity. This study investigated the knowledge, attitudes, intentions and barriers to participation in physical activity among older people recovering from acute illness or injury. METHODS A structured face-to-face questionnaire was developed, incorporating previously validated questions for older people. METHODS Elderly care unit of an urban hospital. METHODS Of 256 consecutively admitted patients, 66 were eligible and 44 (71% female) completed the interview before discharge. MAIN INSTRUMENTS AND OUTCOME MEASURES: Questionnaire using open and closed questions. Baseline data included Barthel Index, gait aid, length of hospital stay and grip strength (indicator of frailty). RESULTS Median age was 83 years (range 67 to 91), median Barthel Index was 18/20 (range 9 to 20), mean hospital stay was 13.7 days (standard deviation 9.7) and 72% (31/43) were frail. Despite hospitalisation, only 23% (10/44) reported 'poor' general health. Knowledge of specific health benefits of physical activity was mixed, and knowledge about hypertension and osteoporosis was poor. Most patients (23/44, 52%) wrongly believed that their habitual activity levels were adequate. Barriers to increasing activity were predominantly related to health, including 'breathing' and 'leg' problems. Intentions towards future physical activity were varied and unrelated to frailty. Needing to rest and relax was a reason given for not being more active. Few patients (5/44, 11%) recalled being advised to be physically active. CONCLUSIONS These patients, potential benefactors from increased physical activity, had mixed knowledge and attitudes towards physical activity which was unrelated to frailty. These data provide insights relevant to the design and delivery of exercise-related health messages and interventions.